This invention relates to the field of preparing phenolic complexes of hexamethylenetetramine. When a water solution of hexamethylenetetramine and a water solution of phenol are combined, a white solid is precipitated. It may be filtered and dried to give a product known as phenotropin. Likewise, when a water solution of hexamethylenetetramine and a water solution of resorcinol are combined, a similar precipitate forms and may be filtered and dried to give a product known as resotropin. Other phenolic compounds may also be combined with hexamethylenetetramine to give similar products. Technical publications make reference to this type of preparation, both in water solution and other solvents such as alcohol. These products are useful in that they by themselves, or with other materials, when heated to higher temperatures, give resins that may be used to bind solids together. They are particularly useful in improving the adhesion of rubber to automobile tire cords, such as rayon, polyester, nylon, fiberglass and steel wire. An article, "The Structure of the Reaction Product of Resorcinol and Hexamethylenetetramine" by E. E. Potapov, I. A. Totorskii, I. D. Khodzhaeva and B. A. Dogadkin, published in SOVIET RUBBER TECHNOLOGY, Volume 24, No. 12, p. 19 (1965) - Translated by P. G. Williams, describes the product resotropin. In the article, "Formation of Resinous Structures in Rubbers During Vulcanization, and Their Effects of Reinforcement" by N. N. Burakova, V. G. Epstein, D. P. Babyuk (Yaroslav. Technol. Inst., Yaroslavl, USSR); Kolloid Zh. 32 (3), 337-41 (1970)(Russ), it is stated that the addition of resotropin with resorcinol-formaldehyde resin to synthetic rubber mixtures increased the mechanical strength and abrasion resistance and decreased the resilience of vulcanizates prepared from these mixtures.
It is also well known that resorcinol and hexamethylenetetramine have desirable effects on vulcanized rubber. There are, however, objections to this use of resorcinol and hexamethylenetetramine because each ingredient must be added to the masticating mixture at a separate and specific stage. Undesirable vapors and/or dust that may have deleterious health effects are liberated during incorporation of the resorcinol and hexamethylenetramine. However, this fuming and dusting is greatly reduced or eliminated when resotropin is used. Such use is therefore considered to be an improvement in the rubber manufacturing art. Other similar complexes herein described are also useful as rubber additives.